If it wasn't twisted to start with, and started to twist when you went to wittlin' on it, you probally took too much off one side. Only you know, we can't see a picture. The advice Rick gave you should be checked for sure. If it is a Flat bow it might be the wood, no big deal, yet, or maybe? If it is a "D" belly Longbow it is probally too much wood off one side. Which might be corrected, partially with Tillering and maybe off-setting the knock grooves.